This invention relates to the field of precision power supplies, in particular in the nuclear magnetic resonance field, and it has as its object a power circuit of a coil, in particular a sample coil, as well as an NMR probe and an NMR spectrometer that comprises such a circuit.
In some applications, it is necessary to use a very specific power, in terms of characteristics and properties of the currents delivered, for circuits that are used in particular or extreme circumstances or contexts.
Such is particularly the case for the power of sample or NMR coils, located in the core of the NMR spectrometers.
In particular in the NMR experiments of the solid, it is necessary to use maximum current specifically in the region that receives the sample (subjected to a rotation at several tens of thousands of rotations per second), i.e., in the center of the coil.
Various power systems have already been proposed to address the above-mentioned need.
These known systems, however, do not provide full satisfaction and exhibit limitations.
The multifrequency analysis is actually generalized, and this is why it is necessary to have several ways to power the coil, at different determined frequencies (each corresponding to a type of core to be detected), each meeting the above-mentioned maximum current condition.
The multifrequency power systems currently proposed (see, for example, U.S. Pat. No. 5,861,748) have a very complicated structure (often very difficult to house readily in the narrow cylindrical space that is set aside for that purpose when the probe that contains the coil is received), whereby each power path has to comprise insulation means relative to the influences of the other paths.
Moreover, these known systems are very non-flexible, and even rigid, in terms of frequency variation of different paths or a change in the number of paths (addition of a path or elimination of a path). Any modification in regard to a path affects all other paths existing within the system and requires an adjustment or changes with regard to the latter, which themselves again have additional repercussions, and in particular because of their dissymmetrical structure.